Wallboard, also known as drywall, plasterboard, sheet rock and gypsum board, is a rigid board used to create interior walls for many if not most modern structures. Wallboard is typically made of layers of fiberboard or paper bonded to a gypsum plaster core. Wallboard is used instead of plaster or wood panels to form walls.
Wallboard is mounted to structural framing using a variety of fastening methods and fastener types. Present-day wallboard installers typically use nails or screws to fasten wallboard to underlying framing supports. The most widely used material of framing support is the wooden stud.
Drywall nails can be used to fasten wallboards to framing supports. Typically, the head of a drywall nail is flat and a sheet rock hammer with a convex face is used for driving the nail into framing supports. The hammer face is convex so that the paper on the wallboard around the head of the nail when driven home will not be broken by the hammer. Also, the convex hammer face creates the depth and expanse of a dimple in the drywall for receiving the appropriate fill. When the nail is properly driven through the drywall and into the stud, the convex face of the hammer drives the nail head, which catches the paper, securing it inside the dimple, created by the hammer. When properly performed, the next step is to fill the dimple with the drywall mud compound (herein after “compound”) covering the nail until the compound in the dimple lies flush with the surface of the drywall. It will be appreciated that the head of the drywall nail resides at the bottom of the dimple and its role is to hold the stretched surface paper of the drywall tightly to the smashed gypsum under the paper of the dimple, securing the paper to the drywall and the drywall to the stud.
Instead of drywall nails, multi-purpose screws can be used to fasten wallboard to studs or other framing supports. Typically such multi-purpose screws have a flat head. Each screw must be recessed beneath the surface of the facing paper leaving a sufficient dimple for the drywall mud; similar to the procedures outlined above for drywall nails.
There has been a trend towards using screws rather than nails over the last several years. Screw heads are larger than nail heads, providing a greater bearing surface to support the wallboard. Additionally, the threaded shank of screw, even though normally shorter than a nail shank, provides greater holding power than a nail. Industry studies by the Gypsum Association have confirmed the greater shear resistance of screws versus nails in gypsum wallboard application. This association recommends in its current application specifications that nails be more closely spaced during installation. Since screw based applications require fewer fasteners this allows for faster application.
Nail pops (also known by some as “poppers”) occur when the wallboard fastener (such as the nail or screw), and portion of the drywall mud covering it, juts out past the plane of the wallboard facing paper forming an unsightly convex bulge. In extreme cases where the drywall mud is stressed to the point of losing its structural integrity it may separate from the wall exposing the wallboard fastener head.
Nail pops can occur immediately after installation, although generally they occur several weeks to several years after the wallboard has been installed. Immediate problems exist due to poor installation, typically when the installer does not drive the fastener sufficiently deeply into the wallboard. The drywall mud, without a dimple of sufficient depth to fill, cannot cover the fastener head while remaining flush with the wall face. The installer prior to a wall being primed and painted typically attempts to remedy problems that are immediately apparent using the current methods which will be described below.
More typically nail pops appear on what was once a perfect wall facing. This occurs either because the drywall has moved and the fastener stayed still, or the fastener moved and the drywall stayed still, or a combination of the two. Most often this is caused with wooden studs shrinking as they dry. During shipment, storage and construction, wood framing is exposed to the natural elements. Wood is a natural material with a cellular disposition to absorb moisture and expand. It is in this moisture laden and expanded state when wallboard is fastened onto it. Once protected by a weather-tight shield and subjected to a heating cycle the wood dries and shrinks. When first fastened, wallboard should mount tightly against the stud (If this is not the case then the problem detailed here is exacerbated). But as the wood between the fastener tip, whose position is fixed, and the edge of the stud shrinks, it pulls away from the back of the panel, leaving a small gap between the framing and the stud. Pressure excerpted against the wall surface by day to day contact is then only restricted by the nail head and filling compound. To exacerbate the scenario above, wood shrinking can also squeeze fasteners out of a stud. Since wood is a natural substance with uneven physical properties and drywall installation is a manual task, variances in fastener integrity can occur. A weak fastener may thus be squeezed out against otherwise secure drywall resulting in a nail pop.
While both nails and screws can become nail pops, the increased shear resistances of screws make them less prone. This is a further reason why use of the screw as a fastener has become more widespread. Improvements to the multi-purpose screw have also been proposed-for example in U.S. Pat. Nos. 6,116,834 and 5,890,860, both to Dorris.
Using nails to secure wallboard to studs was common practice for years and today wallboard nails are still sold for this purpose. Nail pops are a problem for property owners with nail secured wallboard currently and for those that will own properties with nail secured wallboard built in the future.
The best solution for a nail pop is to remove the fastener from the wall. Nails cannot be simply removed from wallboard by traditional methods such as the claw of a hammer of fulcrum type cats paw. These methods are too aggressive for the fragile wallboard. The use of these tools can harm the facing paper and gypsum core causing catastrophic structural damage to the wallboard. Since there is non traditional method for removing the fastener from the wallboard other methods of repair have been employed.
One common practice for repair is to hit the bulging compound or popped nail with a hammer. A variation to this practice is to reset the nail using a traditional nail punch. The nail punch acts as an intermediary between an impact tool and a nail head. Once the nail is reset, compound is applied over the area for aesthetic purposes and the area is repainted or otherwise decorated.
In practice, this method does not address the original cause of failure. The nail is susceptible to pop for many of the same reasons it did the first time. Additionally, since a nail gains its strength via friction, reseating a nail in a hole it previously occupied subjects it to less frictional force. This makes it weaker than it was initially. Finally, since the impact tool's striking surface is larger than the nail head, when striking the nail head, the impact tool damages the brittle wallboard surrounding the nail. This debilitates the integrity of the wallboard. When used expertly, the nail punch focuses the impact tool energy on the nail head reducing some of this effect. In the hands of novice a poorly directed punch can miss the nail head, driving a damaging punch into the brittle wallboard around the nail head.
A second practice employed drives a second nail into the stud with adjacent placement of the second nail head to cover a fractional portion of the first. This method has limitations since the second nail, by design, is as likely to pop as the first if the wallboard is not secure. Further, positioning the second nail over the first nail necessitates driving the first nail deeper into the wallboard to ensure the second nail has a sufficient dimple to fill. Such impact breaks the facing paper and shatters the brittle wallboard surrounding the nail debilitating the integrity of the wallboard.
The third current practice involves driving a wallboard screw into the stud adjacent to the nail. The purpose of the screw is to secure the wallboard. In a variation of this method, two screws are used. The screw(s) do not contact the nail. The nail is repositioned below the plane of the facing paper with a hammer. Compound is applied over the area for aesthetic purposes and the area is repainted or otherwise decorated. This method is effective in securing the wallboard only and does not secure the nail. If the nail was squeezed out due to shrinkage there is nothing to stop this happening again if the wood shrinks further. Additionally, since a nail gains its strength via friction, reseating a nail in a hole it previously occupied subjects it to less frictional force making it weaker than it was initially. Finally, this impact further shatters the brittle wallboard surrounding the nail debilitating the integrity of the wallboard.
The fourth and the only permanent practice is to tear out the existing drywall, replace and secure new wallboard with drywall screws. This is a labor intensive, costly, time consuming, and messy job.